By Deborah Netburn, Los Angeles Times
As the California drought enters its fourth year, scientists are trying to genetically engineer plants that survive on less water.
After adding a new piece of genetic code to their DNA, tomatoes and other plants were able to hold on to more water and survive for as many as 12 days without irrigation.
The tactic, described in the journal Nature, seeks to control how much water a plant loses through the small pores on its leaves known as stomata.
Stomata, as you may remember from biology class, let carbon dioxide in and oxygen out. The size of the opening is regulated by two guard cells that can inflate like little tires.